Cost-effective LED lights replace select streetlights

In collaboration with PG&E, the city of Davis municipality will begin swapping out regular high-pressure sodium (HPS) “yellow” streetlights with those powered by energy efficient light-emitting diodes (LEDs).

In collaboration with PG&E, the city of Davis municipality will begin swapping out regular high-pressure sodium (HPS) “yellow” streetlights with those powered by energy efficient light-emitting diodes (LEDs).

The “Streetlight Conversion Pilot Project” received unanimous support at the Davis City Council meeting last week.

“[It’s a] pilot project to install LED lights on a small scale at selected locations throughout the city,” said city manager Bill Emlen at the meeting.

A total of 327 existing streetlights, or 10 percent of Davis’ streetlights, will be replaced. The city’s federal stimulus funds will pay for the program’s cost of $191,525.

UC Davis professor Dr. Michael Siminovitch who serves as director of the Davis-based California Lighting Technology Center (CLTC) gave a presentation to the council on the benefits of LED technology. He explained LED lights outclass the current HPS technology that dominates Davis streetlights.

“The LED is growing in popularity because it is becoming more efficient and lower-cost and eventually will be a predominant light source in the lighting of our homes and buildings,” Siminovitch said in an e-mail interview.

Standard HPS streetlights last five years before requiring replacement. The new LED streetlights are expected to last approximately 20 years, drastically reducing the labor costs associated with streetlight replacement, said city engineer Bob Clarke at the meeting.

Clarke said Davisites had already been exposed to LED streetlights; several have been installed on Eighth Street.

“I think the main thing that staff wants to do is … gauge how our community responds to the changed lighting,” he said.

LED technology saves vast amounts of energy when paired with motion sensors, ensuring energy does not go to waste when a lit room experiences a period of vacancy. To illustrate the great effect to which motion sensing could be used, Siminovitch showed his audience a nighttime photograph of a multi-tiered UC Davis parking lot drenched in white light.

“This is a typical kind of thing that we see,” he said, referring to the image of the parking lot. “[There were] six cars in this structure at midnight – there’s no reason that we’re lit this brightly.”

Siminovitch and his team of graduate students at the CLTC applied motion-sensing LED technology to the UC Davis campus. Parking lots at the Mondavi Center have all been retrofitted with LED lighting, leading to energy savings of about 60 percent.

The CLTC plans to install LED lighting at other UC campuses through an agreement with the UC Office of the President. For Davis’ streetlight replacement project, however, the organization only provides research and field study data.

They do not feature LED lighting, but many UC Davis dormitories integrate sensor technology. Some students, like first-year Bixby resident Mikaila Snyder, have encountered trouble with the sensors’ insensitivity.

“Unless you’re sitting in the middle in the downstairs lounge, the light turns off every couple minutes,” she said. “[The sensor] only covers a certain area.”

Several councilmembers voiced their support of LED technology before the vote took place. Councilmember Stephen Souza said he had been trying to bring about LED replacements in 2004 and wanted to see all of Davis fitted with them in the future, while Mayor Ruth Asmundson talked about her personal experience with LED lights.

“I’m a fan of LED lightings,” Asmundson said. “I just remodeled my house and everything is LED and sensor and everything.”